Originally Posted by RandomFellow

I don't believe there is any real advantage to doing any prep to the belts other than installing them properly. This whole "dipping and soaking" stuff doesn't seem to have any appreciable positive difference, and can lead to premature belt failure. Just put the belts on fairly loose, and take up the slack as they age.

For excess flashing removal, you can use a hobby knife to whittle it off, or a file to grind it off. Sometimes you do this to make sure there is no binding with the parts rubbing against other parts. Oftentimes, removing the flash its just for looks.